Sheet convey apparatus

ABSTRACT

A sheet convey apparatus includes a top unit, bottom unit, and joint arms. The top unit has a lower boundary surface of a first sheet convey path and rotates in one direction about its one end side as a rotation center. The bottom unit is arranged under the top unit and rotates in the same direction as the top unit about its one end side as a rotation center. The bottom unit has an upper boundary surface of a second sheet convey path connected to the first sheet convey path. The joint arms connect the top and bottom units and rotate the bottom unit to follow rotation of the top unit while an angle formed by the top and bottom units is increased.

BACKGROUND OF THE INVENTION

The present invention relates to a sheet convey apparatus to convey a sheet such as a document used in a copying machine, scanner, facsimile apparatus, or the like and, more particularly, to a sheet convey apparatus having a devised removal mechanism which is used when a sheet such as a document jams in an apparatus that reads image information on each of two sides of a sheet-type document.

In general, in most of sheet-type documents such as a printing product, image information is printed or recorded on the two sides of the document. Various types of sheet convey apparatuses have been proposed which can read image information recorded on the two sides of a document. In most of the document-reading sheet convey apparatuses, the reading surface of the document is moved on a glass platen, and image information is read by a one-dimensional image sensor with a raster-scan scheme. To read image information recorded on the two sides of the document by a sheet convey apparatus of this type, after one reading surface of the document is read, the other reading surface must be moved while it opposes the glass platen. For this reason, an apparatus that reads the two sides of the document automatically is provided with a reversing mechanism which reverses the reading surfaces after one side of the document is read.

An ordinary document-reading sheet convey apparatus conveys various types of documents as a convey target. Accordingly, paper jamming (jam) of the document in a convey mechanism may occur. When the sheet convey apparatus having the reversing mechanism which reverses the reading surfaces of the document is compared to the sheet convey apparatus that reads only one side of the document, the convey path becomes complicated and jam may frequently occur. In view of this, sheet convey apparatuses provided with various types of jamming countermeasures have been proposed.

For example, according to the first proposal suggested by Japanese Patent Laid-Open No. 11-147634, when jamming occurs, it is solved by conveying a document backward. According to the first proposal, when the document stays on a reversal return path, the staying document is conveyed backward from the reversal return path, and is then discharged onto a discharge dray without passing through the reversal return path, so that the document can be removed from the reversal return path easily. When document non-feed jamming occurs, the document is conveyed backward and forcibly discharged onto the discharge tray.

The first proposal is premised on occurrence of light jamming with which a document can be conveyed backward. When the document is to be conveyed backward, if the conveyance itself is impossible as in a case wherein the document winds around a convey roller, the document that has jammed cannot be removed. Also, when the document is partly torn off upon occurrence of jamming, the torn pieces cannot be removed by conveying the document backward.

In view of this, the second proposal as shown in Japanese Patent Laid-Open No. 2002-348052 has been suggested, in which a convey path is divided into several convey path mechanisms in a vertical direction. According to this proposal, when jamming occurs, an upper convey path mechanism is opened by rotating it about a predetermined fulcrum as the center, to expose a lower convey path mechanism. More specifically, a discharge cover surrounding the uppermost portion and side portions of the convey path is opened. Then, a discharge guide arranged at the middle position is opened in a direction opposite to the direction to open the discharge cover, to expose a convey path mechanism arranged at the lowermost portion.

According to the second proposal described above, the convey path is divided into three regions in the vertical direction. The convey path mechanism at the uppermost portion and the convey path mechanism arranged at the middle position are sequentially opened in opposite directions, to expose the convey path mechanism arranged at the lowermost portion. Thus, a document jamming in a convey path formed between the convey path mechanism at the uppermost portion and the convey path mechanism at the middle position, and the document jamming in a convey path formed between the convey path mechanism at the middle position and the convey path mechanism arranged at the lowermost portion can both be removed easily. From the viewpoint of the convey path mechanism at the middle position, the convey path mechanism is provided with a roller to convey the document to the convey path facing the convey path mechanism at the uppermost portion and a roller to convey the document to the convey path facing the convey path mechanism at the lowermost portion. In other words, the convey path mechanism at the middle position is attached with the convey rollers respectively at its position closer to the upper side and its position closer to the lower side. Depending on the state of the jamming, the document sometimes partly jams into the middle position between the upper and lower rollers. In this case, the jamming document is difficult to remove.

To solve this problem, the convey path mechanism at the middle position may be further halved to partition the convey path into four regions in the vertical direction, and the four convey path regions may be opened or closed independently. If, however, the convey path of a particularly compact sheet convey apparatus is partitioned into four convey path mechanisms in the vertical direction, the entire mechanism becomes further complicated. This hinders downsizing and leads to an increase in cost. When jamming occurs at the lowermost side of the convey path, the operator of the sheet convey apparatus must perform a process of sequentially opening the respective convey path mechanisms and a process of sequentially closing the respective convey path mechanisms after the jamming is removed, which is cumbersome.

In the above description, a sheet convey apparatus which reads a document is described. The same problems arise in other sheet convey apparatuses such as a sheet convey apparatus for a printing apparatus that prints images on two sides of a sheet.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a sheet convey apparatus in which jamming can be removed more easily.

In order to achieve the above object, according to the present invention, there is provided a sheet convey apparatus comprising a first convey path unit which has a lower boundary surface of a first sheet convey path and rotates in one direction about one end side thereof as a rotation center, a second convey path unit which is arranged under the first convey path unit and rotates in the same direction as the first convey path unit about one end side thereof as a rotation center, the second convey path unit having an upper boundary surface of a second sheet convey path connected to the first sheet convey path, and a link member which connects the first and second convey path units and follows rotation of the first convey path unit to rotate the second convey path unit while an angle formed by the first and second convey path units is increased.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing the appearance of a document convey apparatus according to an embodiment of the present invention;

FIG. 2 is a sectional view showing the internal structure of the document convey apparatus shown in FIG. 1;

FIG. 3 is a sectional view showing a state wherein a space above the lower unit shown in FIG. 2 is opened;

FIG. 4 is a sectional view showing a dismantled state of the middle unit shown in FIG. 2;

FIG. 5 is a sectional view showing the layout in the use state of the middle unit and lower unit shown in FIG. 2;

FIG. 6 is a sectional view showing a state wherein the middle unit shown in FIG. 2 is opened;

FIG. 7 is a perspective view of the top unit of the middle unit shown in FIG. 2; and

FIG. 8 is a perspective view of the bottom unit of the middle unit shown in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A document convey apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 to 8. Referring to FIG. 1, a document convey apparatus 101 forms the top portion of a document reading apparatus. An apparatus main body portion which is arranged under the document reading apparatus and includes a scanner module formed of an optical system or the like to read a document, an image processing circuit, or a power supply circuit is not shown.

The document convey apparatus 101 has a stacker 102 which extends horizontally so as to be placed on the document reading apparatus main body described above. A document that has been read is stacked on the stacker 102. Two rod-like projections 104 project from the bottom surface of the stacker 102 in a document discharge direction indicated by an arrow 103. A document tray 105 is arranged above the stacker 102 at a predetermined gap. A reading target document is set on the document tray 105 such that the leading edge of the document is inserted in a document insertion port 106. Document guides 107 movable in the widthwise direction of the document are attached before the document insertion port 106 of the document tray 105.

An openable upper unit 108 is arranged on the upper deep side on the document insertion port 106. When a handle 109 located above the center of the document insertion port 106 is lifted upward, the upper unit 108 pivots about the fulcrum as the center, to open the internal space near the inlet of the document insertion port 106. Then, paper jamming (jam) in the apparatus can be removed.

As shown in FIG. 2, the document convey apparatus 101 has three units, i.e., the upper unit 108 and units 115 and 119 that form a document convey space. The upper unit 108 shown in FIG. 1 is arranged at the uppermost portion of the document convey apparatus 101. In the upper unit 108, a total of three rollers, i.e., a guide roll 112 which guides the leading edge of the document to be inserted, a main feed roller 113 which feeds the document inward, and a convey roller 114 are arranged sequentially from the document insertion port 106 on the upper surface side of the document which is to be fed in a direction of an arrow 111 along the document tray 105.

The middle unit 115 is arranged immediately under the upper unit 108. The middle unit 115 also has a mechanism that pivots about a fulcrum as the center, as will be described later. The middle unit 115 has a retard roller 116 in rolling contact with the main feed roller 113 of the upper unit 108, and discharge rollers 117 which discharge the document to the stacker 102 and feed the document into the apparatus again when the two sides of the document are to be read. The discharge rollers 117 are driving rollers driven by a driving source (not shown).

The lower unit 119 is arranged further below the middle unit 115. A glass platen 121 is arranged in an opening formed in the bottom of the lower unit 119. An optical system and reading element (not shown) are arranged at the apparatus main body portion under the glass platen 121, and read the image information of the document passing on the glass platen 121. The lower unit 119 has a convey roller 122 in rolling contact with the convey roller 114 of the upper unit 108, a discharge roller 123 in rolling contact with the discharge rollers 117, and two convey roller pairs, i.e., a pair of convey rollers 124 and pair of convey rollers 125. A flapper 126 which has a wedge-shaped section and switches the document convey direction is arranged at a position before the discharge rollers 117 in the lower unit 119.

A document convey state in the document convey apparatus 101 having the above structure will be described briefly.

An operation of reading only one side of a document will be described. When the document is set on the document tray 105, the guide roll 112 moves downward while rotating, to come into contact with the uppermost layer of the document. Thus, the set document is fed out toward the nip region of the main feed roller 113 and retard roller 116. The document, the leading edge of which is introduced to the nip region, is fed into the apparatus one by one by the main feed roller 113 and retard roller 116. The retard roller 116 rotates in a direction opposite to the rotating direction of the main feed roller 113, to prevent overlapping feed during feeding.

The document passing between the main feed roller 113 and retard roller 116 passes between the pair of convey rollers 114 and 122, then between the pair of convey rollers 124, and is conveyed on the glass platen 121. At this time, the image information on the first surface of the document is read by using a reading element (not shown). After the reading, the document passes between the pair of convey rollers 125, pushes up the distal end of the valve-like flapper 126 from below, passes between the pair of discharge rollers 117 and the discharge roller 123, and is discharged onto the stacker 102. In this manner, the document set on the document tray 105 is fed into the document convey apparatus 101 one by one, and image information on one side (the upper surface of the document set on the document tray 105) of each document is read sequentially.

A case wherein the two sides of the document are to be read will be described. In this case, of the document fed from the document tray 105 into the document convey apparatus 101, the image information on the first surface is read in the manner as described above. As the reading proceeds, the document is fed to the stacker 102 by the pair of discharge rollers 117 and the discharge roller 123 from the leading edge of the document. At this time, the first surface of the document sheet that has been read is located on the lower side.

When the trailing edge of the document sheet reaches the nip region of the pair of discharge rollers 117 and the discharge roller 123, at this timing, the pair of discharge rollers 117 and the discharge roller 123 start to rotate in opposite directions. Thus, the trailing edge of the document sheet passes on the upper surface of the flapper 126, moves forward substantially horizontally through the boundary portion of the middle unit 115 and lower unit 119, and passes between the pair of convey rollers 114 and 122. Consecutively, the document passes between the pair of convey rollers 124 again and is conveyed on the glass platen 121. At this time, the reading element (not shown) reads the image information on the second surface of the document. The document that has been read passes between the pair of convey rollers 125, pushes up the distal end of the valve-like flapper 126 from below, passes between the pair of discharge rollers 117 and the discharge roller 123, and is discharged onto the stacker 102. In this manner, the image information on the two sides of the document sheet are read.

In the document convey apparatus 101 of this embodiment, the upper unit 108 and middle unit 115 can be sequentially opened upward like double doors. In this state, a jamming document can be removed easily, and maintenance such as component exchange can be performed. This will be described mostly concerning the mechanism of the middle unit 115.

Referring to FIG. 3, when the handle 109 is lifted upward, the upper unit 108 is rotated counterclockwise as indicated by an arrow 131 about a fulcrum located at the lower portion of the upper unit 108 as the center. Thus, the upper unit 108 is set still to be upright as a whole at the rear portion of the apparatus. After the upper unit 108 is set upright as described above, the middle unit 115 is rotated clockwise as indicated by an arrow 132 about two rotating shafts 133 as the center. The middle unit 115 is set still as it is upright to oppose the upper unit 108. At this time, the upper unit 108 and middle unit 115 are open like double doors.

The middle unit 115 includes a top unit 142 and bottom unit 144. In the top unit 142, the retard roller 116 is arranged on a feed guide 141, and the top unit 142 rotates about rotating shafts 134 as the center. The bottom unit 144 includes the discharge rollers 117 and a return guide 143, and rotates about the rotating shafts 133 as the center. The top unit 142 and bottom unit 144 are connected to each other through a link (not shown). When the operator lifts the feed guide 141 upward, the top unit 142 and bottom unit 144 both move in the direction of the arrow 132. The rotating shafts 133 serve as a transmission shaft which transmits a load obtained from a solenoid (not shown) as a torque.

When the upper unit 108 and middle unit 115 constitute double doors that open apart, a document jamming between the upper unit 108 and middle unit 115 or between the middle unit 115 and lower unit 119 can be removed easily. Regarding a document jamming in the lower region of the lower unit 119, e.g., between the lower unit 119 and glass platen 121, if it is partly present in the upper space, it can be held with a hand and removed.

As shown in FIG. 4, the middle unit 115 includes the top unit 142 and bottom unit 144, and removable joint arms 151 which connect the two units 142 and 144. The feed guide 141 which forms the top unit 142 has first arm supports 152 at substantially the central portion of its surface that opposes the bottom unit 144. Each arm support 152 has an elongated hole 154 in which a first projection 153 projecting from one end portion of the corresponding joint arm 151 is to be inserted.

The return guide 143 which forms the bottom unit 144 of the middle unit 115 has second arm supports 155 on its surface that opposes the top unit 142. Each second arm support 155 has a hole 157 in which a second projection 156 projecting from the other end portion of the corresponding joint arm 151 is to be inserted.

The joint arms 151 connect both the first and second arm supports 152 and 155 except for a specific case. The specific case refers to a case wherein the discharge rollers 117 attached to the top unit 142 of the middle unit 115 are worn out and are to be exchanged for new ones and a case wherein a paper piece produced when removing a jamming document jams into the middle unit 115 and is to be removed.

Of the middle unit 115, the top unit 142 and bottom unit 144 are pivotal about the different rotating shafts 134 and 133, respectively, as the fulcrums. Accordingly, as shown in FIG. 5, when the middle unit 115 is set on the lower unit 119, the joint arms 151 are substantially parallel to the stacker 102, and the top unit 142 and bottom unit 144 are close to each other as a whole.

In this still state, a free-end-side upper portion 161 of the top unit 142 is held and lifted upward, as shown in FIG. 6. First, only the top unit 142 alone starts to rotate in a direction of an arrow 162 (clockwise) about the rotating shafts 134 as the fulcrum. Simultaneously, one end on the first arm support 152 side of each joint arm 151 (FIG. 5) starts to move upward. Eventually, the bottom unit 144 follows the movement of the joint arms 151 to start rotation in the direction of the arrow 162 about the rotating shafts 133 as the fulcrum.

Therefore, when the middle unit 115 is opened widest as shown in FIG. 6, the angle formed by the top unit 142 and bottom unit 144 is the maximum. In this state, the operator can remove the jamming document by using a space produced above the lower unit 119. When at least one side of each joint arm 151 is removed, the angle formed by the top unit 142 and bottom unit 144 can be further increased. In this state, for example, the operation of removing the paper piece jamming between the units 142 and 144 can be performed easily, as has been described above.

As shown in FIG. 7, a pair of retard roller guides 171 and 172 each having a U-shape are attached to substantially the center of the lower surface of the feed guide 141 which forms the top unit 115, such that the retard roller guides 171 and 172 project at a predetermined gap from each other. Rotating shafts 173 and 174 of the retard roller 116 are urged against the inner surfaces of the retard roller guides 171 and 172 separately by the pressing forces of springs (not shown) through bearings (not shown).

One end of a driving shaft 175 is attached to one rotating shaft 173. The driving shaft 175 transmits a driving force to the rotating shaft 173. The driving shaft 175 is pivotally supported by a bearing portion 177 projecting from the lower surface of one end portion of the feed guide 141. The rotation force of a driving force (not shown) is transmitted to the driving shaft 175 from a rotation force transmission mechanism 178 such as a gear arranged in the vicinity of the driving shaft 175. The rotating shafts 173 and 174 are supported independently of each other by the two springs, as described above. Thus, the position and inclination of the center axis of the retard roller 116 change in accordance with a change in thickness or the like of the document inserted between the retard roller 116 and main feed roller 113 (FIG. 2). However, of the driving shaft 175, the distance from the bearing portion 177 to the rotating shaft 173 is much longer than the distance from the bearing portion 177 to the rotation force transmission mechanism 178. Therefore, even when the position and inclination of the retard roller 116 change, the change will not substantially adversely affect the rotation force transmission mechanism 178, and the driving force can be transmitted smoothly.

The pair of discharge rollers 117, to which a driving force from one driving shaft 181 is transmitted, are attached to that side of the top unit 115 where the rotating shafts 134 are attached. The driving shaft 181 receives a driving force transmitted from another driving shaft 184 through rotation force transmission mechanisms 182 and 183 such as gears. A transmission shaft 185 is arranged, at almost the middle position of the driving shaft 184 and retard roller 116, to be parallel to the driving shaft 184. The transmission shaft 185 transmits a torque load that separates the discharge rollers 117 and 123 (FIG. 2) from each other.

As shown in FIG. 8, the plate-like return guide 143 which forms the bottom unit 144 has the second arm supports 155 on its two end portions. Under the two end portions, bearing portions 193 and 194 axially support transmission shafts 191 and 192 coaxial with and connected to the rotating shafts 133, respectively.

One transmission shaft 191 transmits a torque load through the transmission shaft 185 (FIG. 7) to the pair of discharge rollers 117 and the discharge roller 123 applied with pressing forces by springs (not shown), to separate the rollers 117 and the roller 123 from each other. The other transmission shaft 192 transmits a driving force to the driving shaft 184 (FIG. 7), to rotatably drive the pair of discharge rollers 117.

In the document convey apparatus 101 of this embodiment having the above structure, while the upper unit 108, middle unit 115, and lower unit 119 are sequentially laid on each other, as shown in FIG. 2, the document is inserted between the main feed roller 113 and retard roller 116. At this time, the main feed roller 113 rotates in the document convey direction, and the retard roller 116 rotates in a direction opposite to the document convey direction with a predetermined torque. The document is inserted between the upper unit 108 and middle unit 115, and is read while it passes through the lower unit 119. After that, the document is discharged onto the stacker 102.

Assume that the two sides of the document are to be read. As soon as the trailing edge of the document passes the flapper 126, a sensor (not shown) detects this trailing edge. At this time point, the discharge rollers 117 start to rotate backward. Thus, the document passes above the flapper 126 through the gap between the flapper 126 and the return guide 143 (FIG. 3) of the middle unit 115, and is guided to the upper portion of the glass platen 121 again. Then, the other side of the document is read. When the document passes on the flapper 126, as the top unit 142 is arranged as the guide plate above the flapper 126, jamming does not occur frequently at this portion. When the image information on the two sides of the document is read, the document is discharged onto the stacker 102.

When the lengths of the joint arms 151 are changed, the open angle of the top unit 142 and bottom unit 144 of the middle unit can be adjusted. The longer the joint arm 151, the larger the open angle, and the document jamming between the top unit 142 and bottom unit 144 can be removed more easily. Note that design must be performed such that when the joint arms 151 rotate, components do not interfere between the units 142 and 144.

In the above embodiment, a document convey apparatus which conveys a document is described. The present invention can be similarly applied to a sheet convey apparatus which conveys a sheet other than a document by a similar mechanism.

In the above embodiment, the joint arms 151 are attached between the top unit 142 and bottom unit 144, and the top unit 142 and bottom unit 144 rotate about different rotating shafts as the centers, respectively. Thus, the gap between the top unit 142 and bottom unit 144 which is formed by the joint arms 151 is changed. Alternatively, if the top unit 142 and bottom unit 144 share one rotating shaft and a stretchable elastic member is arranged between the top unit 142 and bottom unit 144, when the top unit 142 is rotated in an opening direction in the same manner, the gap between the top unit 142 and bottom unit 144 can be enlarged.

Furthermore, in the above embodiment, the present invention is applied to a sheet convey apparatus including three units, i.e., the upper unit 108, middle unit 115, and lower unit 119. The present invention can similarly be applied to a sheet convey apparatus including one or two units, or four or more units.

As has been described above, according to the present invention, a unit which should originally be formed as one convey path unit includes the first and second convey path units. When the first and second convey path units are rotated in predetermined directions and opened, the angle formed by the first and second convey path units increases. Hence, even if a sheet jams into the apparatus, it can be removed easily. In addition, as the first and second convey path units rotate together, the operation of opening/closing the first and second convey path units is not cumbersome.

The link member can be removed from at least one of the first and second convey path units. When the link member is removed, the angle formed by the first and second convey path units can be further increased. Then, for example, the operation of exchanging convey rollers attached to these units can be performed easily.

As the second convey path unit has a guide surface, the occurrence rate of jamming can be decreased. Moreover, when compared to a sheet convey mechanism that has no guide surface at this portion, the structure of the entire unit including the first and second convey path units can be simplified. 

1. A sheet convey apparatus comprising: a first convey path unit which has a lower boundary surface of a first sheet convey path and rotates in one direction about one end side thereof as a rotation center; a second convey path unit which is arranged under said first convey path unit and rotates in the same direction as said first convey path unit about one end side thereof as a rotation center, said second convey path unit having an upper boundary surface of a second sheet convey path connected to said first sheet convey path; and a link member which connects said first and second convey path units and rotates said second convey path unit to follow rotation of said first convey path unit while an angle formed by said first and second convey path units is increased.
 2. An apparatus according to claim 1, wherein positions of the rotation centers of said first and second convey path units differ between said units, and said link member comprises a rod-like member two end portions of which are pivotally held by said first and second convey path units.
 3. An apparatus according to claim 1, wherein said link member comprises a stretchable member two end portions of which are attached to said first and second convey path units.
 4. An apparatus according to claim 3, wherein said link member is removable from at least one of said first and second convey path units.
 5. An apparatus according to claim 1, further comprising an upper unit arranged above said first and second convey path units, and a lower unit arranged below said first and second convey path units, wherein said first and second convey path units form a middle unit sandwiched by said upper unit and lower unit from above and below.
 6. An apparatus according to claim 5, wherein said upper unit has a main feed roller serving as a driving roller which feeds a sheet into the apparatus, and said middle unit has a separation roller which is arranged in rolling contact with said main feed roller and receives a rotation force that rotates said separation roller in a direction opposite to said main feed roller.
 7. An apparatus according to claim 1, wherein said upper boundary surface of said second sheet convey path is formed of a guide member which guides sheet conveyance.
 8. An apparatus according to claim 1, wherein when said first and second convey path units are interlocked to rotate, a space above said second sheet convey path is opened.
 9. A sheet convey path comprising: first and second convey path units which are formed of different members, each of two opposing surfaces of each of said members serving to form one boundary surface of each of different convey paths for conveyance of one sheet, and which open a space above said convey paths formed by a lower boundary surface, among said boundary surfaces of said members, and an upper boundary surface of another member arranged below said members when said members are rotated simultaneously in predetermined directions each about one end side thereof as a rotation center, and a link member which connects said first and second convey path units to each other, and moves said second convey path arranged on a lower side to follow said first convey path unit, when said first convey path unit arranged on an upper side, of said first and second convey path units, receives a rotation force in a predetermined direction, while an angle formed by said first and second convey path units is increased. 